Problem from Mastering Physics

I really don't know how to find the acceleration at the intersection.
You are driving to the grocery store at 19 m/s. You are 140 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.77 s and that your car brakes with constant acceleration.
I have found that d1=130m
I tried to find the acceleration and I got 25, but it's wrong.
Could someone help me with this problem?